migrate_start_postcopy: Command to trigger transition to postcopy

Once postcopy is enabled (with migrate_set_capability), the migration
will still start on precopy mode.  To cause a transition into postcopy
the:

  migrate_start_postcopy

command must be issued.  Postcopy will start sometime after this
(when it's next checked in the migration loop).

Issuing the command before migration has started will error,
and issuing after it has finished is ignored.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
This commit is contained in:
Dr. David Alan Gilbert 2015-11-05 18:10:56 +00:00 committed by Juan Quintela
parent eb59db53a4
commit 4886a1bcb7
7 changed files with 75 additions and 0 deletions

View file

@ -1005,6 +1005,21 @@ STEXI
@item migrate_set_parameter @var{parameter} @var{value}
@findex migrate_set_parameter
Set the parameter @var{parameter} for migration.
ETEXI
{
.name = "migrate_start_postcopy",
.args_type = "",
.params = "",
.help = "Switch migration to postcopy mode",
.mhandler.cmd = hmp_migrate_start_postcopy,
},
STEXI
@item migrate_start_postcopy
@findex migrate_start_postcopy
Switch in-progress migration to postcopy mode. Ignored after the end of
migration (or once already in postcopy).
ETEXI
{

7
hmp.c
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@ -1293,6 +1293,13 @@ void hmp_client_migrate_info(Monitor *mon, const QDict *qdict)
hmp_handle_error(mon, &err);
}
void hmp_migrate_start_postcopy(Monitor *mon, const QDict *qdict)
{
Error *err = NULL;
qmp_migrate_start_postcopy(&err);
hmp_handle_error(mon, &err);
}
void hmp_set_password(Monitor *mon, const QDict *qdict)
{
const char *protocol = qdict_get_str(qdict, "protocol");

1
hmp.h
View file

@ -69,6 +69,7 @@ void hmp_migrate_set_capability(Monitor *mon, const QDict *qdict);
void hmp_migrate_set_parameter(Monitor *mon, const QDict *qdict);
void hmp_migrate_set_cache_size(Monitor *mon, const QDict *qdict);
void hmp_client_migrate_info(Monitor *mon, const QDict *qdict);
void hmp_migrate_start_postcopy(Monitor *mon, const QDict *qdict);
void hmp_set_password(Monitor *mon, const QDict *qdict);
void hmp_expire_password(Monitor *mon, const QDict *qdict);
void hmp_eject(Monitor *mon, const QDict *qdict);

View file

@ -127,6 +127,9 @@ struct MigrationState
int64_t xbzrle_cache_size;
int64_t setup_time;
int64_t dirty_sync_count;
/* Flag set once the migration has been asked to enter postcopy */
bool start_postcopy;
};
void process_incoming_migration(QEMUFile *f);

View file

@ -668,6 +668,28 @@ void qmp_migrate_set_parameters(bool has_compress_level,
}
}
void qmp_migrate_start_postcopy(Error **errp)
{
MigrationState *s = migrate_get_current();
if (!migrate_postcopy_ram()) {
error_setg(errp, "Enable postcopy with migration_set_capability before"
" the start of migration");
return;
}
if (s->state == MIGRATION_STATUS_NONE) {
error_setg(errp, "Postcopy must be started after migration has been"
" started");
return;
}
/*
* we don't error if migration has finished since that would be racy
* with issuing this command.
*/
atomic_set(&s->start_postcopy, true);
}
/* shared migration helpers */
static void migrate_set_state(MigrationState *s, int old_state, int new_state)

View file

@ -701,6 +701,14 @@
'data': { 'protocol': 'str', 'hostname': 'str', '*port': 'int',
'*tls-port': 'int', '*cert-subject': 'str' } }
##
# @migrate-start-postcopy
#
# Switch migration to postcopy mode
#
# Since: 2.5
{ 'command': 'migrate-start-postcopy' }
##
# @MouseInfo:
#

View file

@ -717,6 +717,25 @@ Example:
<- { "return": {} }
EQMP
{
.name = "migrate-start-postcopy",
.args_type = "",
.mhandler.cmd_new = qmp_marshal_migrate_start_postcopy,
},
SQMP
migrate-start-postcopy
----------------------
Switch an in-progress migration to postcopy mode. Ignored after the end of
migration (or once already in postcopy).
Example:
-> { "execute": "migrate-start-postcopy" }
<- { "return": {} }
EQMP
{
.name = "query-migrate-cache-size",
.args_type = "",